I would replace the ignition switch right away. I would also hook the clutch safety switch back up. My understanding is that without it, you can't pre-heat with the glow plugs. You'll hate life without that function. I've been brush hogging that heck out of my blackberrys/other shrubs and brush, and haven't had a problem. Just be mindful and watch what you're doing. You don't need the key on to run the tractor (only to turn the starter), but you do need it for pre-heating, and lights. The flashers won't turn on, unless you have the lights turned on.
Sounds like this guy wasn't much of a mechanic, and really didn't care much to keep things right. I would do a full fluid change right away as well. He also must have either worked it REALLY hard, or did a lot of traveling on roads. My 1715 has 1268 hours on it, and the factory tires have about 55% tread left on the front, and probably 70% in the rear.
Once you go through it, you'll have a excellent tractor! These are very sought after, and people absolutely love them. You'll have fun getting to know it, and by the time you're done, you'll have something you're really proud of.
Cheers!
Chris
